Whoops, I spoke to soon. Your 50 BTC note is still 3 BTC over spot. If you can make a single 1 BTC note and profitably sell it at 1.30 BTC, then you should be able to make a single 50 BTC note and profitably sell it at 50.30 BTC.

The upside is that people who don't want to screw around with software will have a reliable way to get a very secure savings wallet, possibly the most secure wallet available to a non-technical person. If we're jamming three or four holograms on this thing, the material costs are already somewhat expensive anyway.

Companies claiming they got hacked and lost your coins sounds like fraud so perfect it could be called fashionable. I never believe them. If I ever experience the misfortune of a real intrusion, I declare I have been honest about the way I have managed the keys in Casascius Coins. I maintain no ability to recover or reproduce the keys, not even under limitless duress or total intrusion. Remember that trusting strangers with your coins without any recourse is, as a matter of principle, not a best practice. Don't keep coins online. Use paper or hardware wallets instead.

Whoops, I spoke to soon. Your 50 BTC note is still 3 BTC over spot. If you can make a single 1 BTC note and profitably sell it at 1.30 BTC, then you should be able to make a single 50 BTC note and profitably sell it at 50.30 BTC.

The question you have to ask yourself is, even at very large orders, what is the absolute CHEAPEST I can sell 1 note worth. If the absolute cheapest amount you can sell a note for is 30 Bit cents over spot, then you'll have to make THAT your target goal for the bulk pricing. Notice above how I made it so that at 1000 notes ordered, the cost per note is 10 Bit cents over spot. Simply adjust that to be 30 Bit cents over spot, and re-adjust the rest to be slightly higher. In that case if somebody one orders, say, 1 note all by itself the cost might be 55 Bit cents above spot. Make sense?

Whoops, I spoke to soon. Your 50 BTC note is still 3 BTC over spot. If you can make a single 1 BTC note and profitably sell it at 1.30 BTC, then you should be able to make a single 50 BTC note and profitably sell it at 50.30 BTC.

I brought the price down significantly for the 50 BTC bill, but I do still include a percentage in my markup. I consider it a handling fee for the risk of managing $250 worth of cash. You may think that is no big deal as a transaction is a transaction, but I get a little nervous when I have to handle that much for someone. If someone ordered a hundred 50BTC bills, I would probably need to take the day off from work just to make sure I was ultra careful with each one being loaded.

If the markup is a big deal, just buy the open denomination bill, which is the cheapest one available. You can load it with whatever you like, and I don't have to handle your money for you.

Also, note that I just added "a stack of 100 1BTC bills" to the shopping system. There is a nice discount there, and coincidentally it is priced about the same as what you expected in your chart.

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

I brought the price down significantly for the 50 BTC bill, but I do still include a percentage in my markup. I consider it a handling fee for the risk of managing $250 worth of cash. You may think that is no big deal as a transaction is a transaction, but I get a little nervous when I have to handle that much for someone. If someone ordered a hundred 50BTC bills, I would probably need to take the day off from work just to make sure I was ultra careful with each one being loaded.

Maybe we should share some notes on how to efficiently fund bills.

For me, loading BTC on coins gives me virtually no anxiety, even if I'm doing 2000+ BTC in a single run. I have a rock solid way to track and load them. I am using a database to track their loading status, and everything is crosschecked against the master list of bitcoin addresses so I don't load the wrong thing. Also since I keep my BTC on paper wallets, I only unpaperize the BTC I am about to load right then and there - so there's no risk that I send all my BTC to the wrong place by fat fingering an amount.

Companies claiming they got hacked and lost your coins sounds like fraud so perfect it could be called fashionable. I never believe them. If I ever experience the misfortune of a real intrusion, I declare I have been honest about the way I have managed the keys in Casascius Coins. I maintain no ability to recover or reproduce the keys, not even under limitless duress or total intrusion. Remember that trusting strangers with your coins without any recourse is, as a matter of principle, not a best practice. Don't keep coins online. Use paper or hardware wallets instead.

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely?

As far as 0.06 BTC markup. You are aware there is no central bank which can subsidize printing costs. Things like material, labor, custom holograms, etc do time take and resources. Your expectations may be a little unrealistic.

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely?

As far as 0.06 BTC markup. You are aware there is no central bank which can subsidize printing costs. Things like material, labor, custom holograms, etc do time take and resources. Your expectations may be a little unrealistic.

D&T - Thank you, you are now my official spokesperson for all pricing issues.

Also, anyone is welcome to undercut me if I charge too much. You could probably charge much less and still make a profit if you have access to cheap labor.

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely?

As far as 0.06 BTC markup. You are aware there is no central bank which can subsidize printing costs. Things like material, labor, custom holograms, etc do time take and resources. Your expectations may be a little unrealistic.

Well, obviously there is going to be markup. But 3 BTC markup on a 50 BTC note is too steep for me. So is 17 BTC on 100 1 BTC notes.

I'm sure, eventually, there will be competition in the Bit bill market, driving prices down.

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely?

As far as 0.06 BTC markup. You are aware there is no central bank which can subsidize printing costs. Things like material, labor, custom holograms, etc do time take and resources. Your expectations may be a little unrealistic.

Well, obviously there is going to be markup. But 3 BTC markup on a 50 BTC note is too steep for me. So is 17 BTC on 100 1 BTC notes.

I'm sure, eventually, there will be competition in the Bit bill market, driving prices down.

I am just giving room for a competitor to step in and eat my lunch. If I charged too little, than what would be the incentive for anyone else to break into the market.

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely?

As far as 0.06 BTC markup. You are aware there is no central bank which can subsidize printing costs. Things like material, labor, custom holograms, etc do time take and resources. Your expectations may be a little unrealistic.

Well, obviously there is going to be markup. But 3 BTC markup on a 50 BTC note is too steep for me. So is 17 BTC on 100 1 BTC notes.

I'm sure, eventually, there will be competition in the Bit bill market, driving prices down.

I am just giving room for a competitor to step in and eat my lunch. If I charged too little, than what would be the incentive for anyone else to break into the market.

Person 1: From the random private key (a) and the public key created by person 2 (B) calculate the final public key (F = a*B) [Note a*B = a*b*G which makes the final private key a*b] Calculate the final public key address of the final public key (F)

Quote

Person 2: From the random private key (b) and the public key created by person 1 (A) calculate the final public key (F = b*A) [Note b*A = b*a*G which makes the final private key b*a] Print the private key (b) on the bill - and cover it with a sticker to hide it Calculate the public key address of public key F and print it on the bill Send the bill to person 1

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Person 1 Finally print the private key (a) on the bill Can match the public key address calcluated above with the public key address on the bill

Thanks. I really like this elliptical curve crypto - it is a lot more fun than RSA.

Our family was terrorized by Homeland Security. Read all about it here: http://www.jmwagner.com/ and http://www.burtw.com/ Any donations to help us recover from the $300,000 in legal fees and forced donations to the Federal Asset Forfeiture slush fund are greatly appreciated!

First, private keys are just very large numbers but public keys are actually a pair of two very large numbers representing the x, y coordinates of a point on an elliptical curve.

I use lower case letters to represent elements of the selected finite field and capital letters to represent points in the selected elliptical curve group.

So: a = b*c represents simple modulo multiplication for the selected finite field, short for a = ((b*c) mod p)

And: A = B + C would represent the defined point addition operation on the selected elliptical curve group. This is not simple addition, it is the way we define the addition of two points on the elliptical curve.

Then A = a*G is just G+G+G+G+...+G, a times. And in this case the * represents the defined scalar multiplication operation for the selected finite field over the selected elliptical curve group - so no this is not simple multiplication it is a pretty involved function and can be a bit time consuming.

Clear as mud?

Our family was terrorized by Homeland Security. Read all about it here: http://www.jmwagner.com/ and http://www.burtw.com/ Any donations to help us recover from the $300,000 in legal fees and forced donations to the Federal Asset Forfeiture slush fund are greatly appreciated!

Or maybe I am complete off. Can you provide an example of (F = b*A) using real numbers.

In this case, A is not a 256-bit number. In programming terms, it is an object, a structure with two 256-bit numbers known as X and Y. The definition of "multiplication" has been redefined - in C++ terms, the "multiplication operator" has been overridden with a far more complex definition. So, F = b * A means "Perform the elliptic curve multiplication operation on point object A, using the 256-bit integer b as a parameter"... this operation returns another point object, not a number.

And 256 bit overflow is not a concern once you understand what "finite field" is. Yes, there is overflow, and the overflow is thrown away - but you must critically understand that the overflow doesn't happen at 2^256, it happens at another number known as N, which is a 256-bit number, but smaller than 2^256. So when you do scalar multiplication and the answer exceeds N, you handle the overflow by dividing by N and keeping the remainder (not dividing by 2^256 and keeping the remainder, as "handling 256 bit overflow" strictly means).

N is a constant you can find on the bitcoin wiki, search for "secp256k1".

Companies claiming they got hacked and lost your coins sounds like fraud so perfect it could be called fashionable. I never believe them. If I ever experience the misfortune of a real intrusion, I declare I have been honest about the way I have managed the keys in Casascius Coins. I maintain no ability to recover or reproduce the keys, not even under limitless duress or total intrusion. Remember that trusting strangers with your coins without any recourse is, as a matter of principle, not a best practice. Don't keep coins online. Use paper or hardware wallets instead.

Our family was terrorized by Homeland Security. Read all about it here: http://www.jmwagner.com/ and http://www.burtw.com/ Any donations to help us recover from the $300,000 in legal fees and forced donations to the Federal Asset Forfeiture slush fund are greatly appreciated!

This is the number I'm calling N. The number above you have called p is the number I would call p as well, but I don't think that's the right number for this purpose.

THe person who has it wrong could very well be me, becuase chances are I implemented it, saw it worked, and forgot about it further. I could have had a brainfart and used the other number instead, but this is the number I always thought i used.

Companies claiming they got hacked and lost your coins sounds like fraud so perfect it could be called fashionable. I never believe them. If I ever experience the misfortune of a real intrusion, I declare I have been honest about the way I have managed the keys in Casascius Coins. I maintain no ability to recover or reproduce the keys, not even under limitless duress or total intrusion. Remember that trusting strangers with your coins without any recourse is, as a matter of principle, not a best practice. Don't keep coins online. Use paper or hardware wallets instead.

According to the docs p is the prime number specifying the finite field used and n is the prime number specifying the order of G.

So I think the number p should be used for all the finite field math operations, for example a = b*c mod p

And n has something to do with G (the base point of the system).

So, I believe that I am correct in that the "overflow" in the finite field math is at p.

I am trying to remember exactly what n means and how it is used. I remember reading it and understanding it at one point but I forget now exactly what it means.

If I find the reference again I will post it here.

We need to nail this down because it affects the all important calculation of the final private key f = a*b mod ?

So you could easily experimentally determine which one it is. Calculate the final private key using each number and let us know which one calculates the correct final private key.

Our family was terrorized by Homeland Security. Read all about it here: http://www.jmwagner.com/ and http://www.burtw.com/ Any donations to help us recover from the $300,000 in legal fees and forced donations to the Federal Asset Forfeiture slush fund are greatly appreciated!